St Paul's Cathedral is now £20. We have a (very) ancient ancestor in one of the tombs in there. It would be nice, if we have a visiting couple of relatives we are showing round London, to pop in and show this to them, which not that many years ago we would readily do. But now that's £80. To see our own family which they have made (a very small) part of their attraction.
Tell them you require to be let in for free or you'll take your ancestor somewhere else.